In my quick experience with this, the default parking page is a generic dreamhost page that just says that it's coming without contact info. Without a hosting account, you might not be able to do that.
But, you could use a redirect to your old site (or even I think a page on that site that has contact info) or you may be able to "cloak" and refer to your old site but make it LOOK like it's the new one.
If you want more help then that, let us know. The panel will let you do almost all of that.